Design and construction of jigs and fixtures



I 1962 J. WHARTON 3,030,831

DESIGN AND CONSTRUCTION OF JIGS AND FIXTURES Filed Nov. 5, 1959 I Attorney\ United States Patent Ofitice fiddfifi Patented Apr. 24, 19623,030,831 DESIGN AND CQNSTRUCTION F JIGS AND FIXTURES John Wharton, 151London Road, St. Alhans, England;

Alice Mary Wharton, .executrix of said John Wharton,

deceased, assignor to Wharton & Wilcocks Limited,

Hertford, Hertfordshire, England Filed Nov. 3, 1959, Ser. No. 850,737 1Claim. (Cl. 7762) This invention relates to the design and constructionof jigs and fixtures.

In the specification to Patent No. 2,676,413 there is described andclaimed a jig or fixture for use in the manufacture and production ofcomponent elements to accurate dimensions, such jig or fixture beingbuilt up of a multiplicity of interchangeable standard elements eachfurnished with one or more T-slots, or one or more tenon slots, or oneor more tenons or any combination of T- slots, tenon slots or tenonsadapted to locate and secure the said standard elements relatively toone another and to a base or to a frame or frames attached to said base,on which they are mounted and secured to form a complete unitarystructure.

For a drilling operation on a component, a fixture constructed inaccordance with the disclosure of the aforesaid specification may, forexample, comprise a base member having fixedly mounted thereon aso-called stop element. Tenoned to the upper end of the stop element isa rectangular block having upstanding lugs at each corner adapted toguide the stem of a clamping member for holding a drill bush or thelike, said stem being flat and having therein an elongated slot throughwhich passes a securing bolt, the latter passing up from the base memberand also through the stop element and guide block, a locking nut beingengaged with the upper or outer end of said bolt and turned until itfirmly secures the stem of the clamping member to said block. Normally aclamping plate or the like is arranged between the locking nut and thestem of the clamping member.

The provision of the elongated slot in the stern of the clamping memberenabled the position of the clamping member with respect to thesupporting guide block to be adjusted as required. The rigidity of theseparts after adjustment, however, depends largely on the friction betweenthem due to bolting, and it is possible for the proper adjustmentthereof to be upset, for example, by a sharp accidental blow. Thepresent invention has for its main object to provide improved means forovercoming this disadvantage.

In the accompanying drawings:

FIG. 1 shows an arrangement as heretofore proposed, and

FIG. 2 shows an arrangement in accordance with this invention.

With reference to FIG. 1 of the accompanying drawings, which shows anarrangement as heretofore proposed, there is shown or indicated thereina base member I having fixedly mounted thereon a stop element 2, asdescribed in the Specification to the aforesaid patent. Tenoned to theupper end of the stop element is a rectangular block 3 having upstandinglugs 3 at the corners thereof adapted to guide the stem of a clampingmember 4 for holding a drill bush or the like 5, said stern beingflattened and having therein an elongated slot 6 for the passage ofmeans (described in detail hereinafter) for securing it to the guideblock.

In the arrangement shown in FIG. 1 a single securing bolt (not actuallyvisible) passes up from the base memher 1 through the stop element 2,the guide block 3 and the slot in the stem of the clamping member 4, alocking nut 7 being engaged with the upper or outer end of said bolt andturned until it firmly secures the stem of the clamping member to theguide block. A clamping plate 8 is disposed between the locking nut 7and the stem of the clamping member.

The clamping member 4 is provided at the end thereof remote from thebush holder 5 with a downwardly directed plate 10 disposed in a planeparallel to the end face of the supporting guide block 3, said platehaving therein an aperture or slot which is arranged in line with atapped hole in the supporting guide block. A threaded rod 11 is engagedin said tapped hole, being secured by a locking nut 12, and passesfreely through the aperture or slot in the plate It). Thus when theposition of the clamping member 4 is being adjusted the plate 10 slidesover the rod 11, locking nuts 13 being provided on the latter forengaging the opposite sides of the plate and so locking it and theclamping member in any desired correctly adjusted position.

In the arrangement in accordance with this invention, as shown in FIG.2, instead of the single screwed rod 11 as described above, there isprovided a pair of parallel spaced rods 20 which extend from a plate,not visible, attached to the guide block 3 by holding screws, and oneach of these is mounted a plurality of cylindrical members or discs 21of known accurate dimensions, these members or discs being separated byspacers, also of known dimensions but of smaller diameter wherebyannular slots 22 are provided between the adjacent members or discs 21.The cylindrical members or discs 21 with the spacers between them aresecured on their respective rods by nuts 23 engaging the ends of thelatter. The plate ltl on the clamping member 4 is provided withapertures 24 through 7 which the cylindrical members or discs can freelypass and pivoted to the plate is a plurality of levers 25each of whichhas an edge portion 25 of the same thickness as the spacers, thearrangement being such that this edge portion can be engaged in theslots 22 between the cylindrical members or discs on one of the rods.The slots 22 between the cylindrical members or discs on one rod arestaggered with respect to those on the other, one lever 25 beingassociated with each rod. Such arrangement provides a range of fixedsettings for the clamping member 4, any one of which can very readily beadopted.

I claim:

A jig or fixture built up of a plurality of interchangeable standardelements comprising a base having a flat upper surface with a pluralityof T-slots extending lengthwise in the upper face of the base, a stopelement comprising a rectangular block having a square horizontal crosssection, a tenon on the under surface of said block, a tenon slot in atleast one other surface of the block, means for securing the stopelement on the base with the tenon there on located in a T-slot in thebase, such means comprising a bolt engaged in the T-slot in the base andpassing through the stop element perpendicularly to said tenon, and alocking nut cooperating with said bolt, a guide block mounted on theouter surface of said stop element, means for engaging said guide blockin the tenon slot in the stop element positively to locate the guideblock against turning, spaced guide lugs on said guide block, a clampmemher, for holding a drill bush, adjustably mounted on the guide blockbeing slidably engaged by and between said guide lugs, the said securingbolt passing also through the guide block and clamp member whereby they,together with the stop element, are secured to the base, a plate securedto one end of said clamp member and extending at right angles thereto,rod means fixed in said guide block and extending therefrom in parallelrelationship with the clamp member, a plurality of discs mounted on saidrod means, spacer elements also mounted on said rod means and separatingsaid discs one from the other, said rod means with the discs thereonextending through an aperture in said plate, a locking lever pivotallymounted on said plate and adapted selectively to be engaged in the spacebetween any two of said discs thereby to ensure rigidity between theclamp member and the guide block after the clamp member has beenadjusted to any desired position.

References Cited in the file of this patent UNITED STATES PATENTSWharton et al Apr. 27, 1954 OTHER REFERENCES

